Beryllonite

Beryllonite crystals are colourless, white or pale yellow, but its weak fire and low dispersion make it a dull gemstone. Additionally, its softness, perfect cleavage, and brittle fracture make it fragile, although with care it may be faceted for collectors.

Beryllonite is a pegmatite mineral, found associated wuth the minerals phenakite and berylin in Maine in the United States. It is also present in Finland and Zimbabwe, but remains an uncommon gem.

Beryllonite is name after the beryllium content in its chemical composition. It's been wrongly identified as other colourless gemstones of low dispersion.

Beryllonite Properties

Chemical Composition: 
Sodium beryllium phosphate
Crystal System / Forms: 
Monoclinic
Hardness: 
5.5
Specific Gravity: 
2.83
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.55-1.56 / 0.009
Magnification: 
In rough, cleavage planes are visible.
Sources: 
United States, Finland and Zimbabwe.
Cuts & Uses: 
Brilliant, Cushion, Pendeloque